In addition to the deaths, injuries and damage to the city of Qingdao, Friday's explosion has resulted in the threat of oil-based pollution of the ocean.

On Sunday, the wind was high on the waters near Jiaozhou Bay, with speeds reaching 100 kilometers at night, according to the metrological office.

Heavy seas helped to spread the oil across the surface of the water, but a favorable wind drove the larger oil spills inland, toward a containing sea wall. Officials from Qingdao Maritime Bureau said the weather was providing good conditions for cleaning up the pollution. Despite the high winds, large waves and freezing temperatures, staff from the bureau spent Sunday throwing oil-absorbent pads into the water.

At a news briefing on Saturday, officials said that the polluted area of the Yellow Sea had grown to more than 10,000 square meters, from the 3,000 square meters reported in the immediate aftermath of the explosion on Friday.

Huang Haiyan, deputy director of the Qingdao Maritime Bureau, said that booms - placed at the point where the storm drains empty into the waters of the Yellow Sea to prevent the oil from spreading - had become ineffectual after catching on fire. That, combined with the influence of the tide, had resulted in the area of pollution expanding.

However, a post on the micro blog of China Petroleum and Chemical Corp, which operates the ruptured pipeline, contradicted the bureau's claims. It said booms set up across the mouth of Jiaozhou Bay had stopped the flow of crude oil from the storm drains, and prevented more oil from entering the bay's ecosystem. More than 150 personnel and 18 ships are involved in the operation. Eight successive booms have been placed in the water to prevent the pollution from spreading.

Liu Xiankun, head of the maritime office at Qingdao Maritime Bureau, who oversaw the operations in the bay on Sunday, refused to comment on the progress of the work, or to provide any information on the scale of the pollution.

- He Na and Yang Yang